Assign variables to positions in matrix

I'm sure this is a stupid question, but how does one define variables as positions in a matrix? For example, in matrix algebra, if I set up a matrix equation such that B=inv(A)*C, how can I define x and y such that B=[x;y]?

Answer 1

[David Young]

Alternatively, do you mean that you have B and want to divide it into two parts? If B is 2x1 or 1x2 you can do

x = B(1);
y = B(2);

More generally, if you want to split B into a top half and a bottom half, you could do

splitrow = ceil(size(B, 1)/2);
x = B(1:splitrow, :);
y = B(splitrow+1:end, :);

This divides B in half, as far as possible. Your condition B=[x;y] is satisfied for any legal value of splitrow.

[Patrick Star]

Thanks! x=B(1) and y=B(2) is exactly what I was looking for.

Answer 2

[Sean de Wolski]

B = [3;4]; %column vector
B = [3 4]; %row vector
B = [1 2; 3 4]; %2x2 matrix.

Ps

B = A\C; %is better than inv(A)*C

[Patrick Star]

I know how to create a matrix, but I just need to know how to assign variables to values in a matrix.

Also, B=C/A does not work because you cannot divide matrices like that with different dimensions.

[Sean de Wolski]

Note the difference in our slashes \/!